Snap-action plunger-operated electrical switch



March 22, 1966 MASARU SUZUKI SNAP-ACTION PLUNGER-OPERATED ELECTRICALSWITCH 2 Sheets-Sheet 1 Filed Aug. 28, 1963 WZasaIru 8 2 mi INVENTOR.

BY WWW W6 March 22, 1966 MASARU SUZUKI 3,242,282

SNAP-ACTION PLUNGER-OPERATED ELECTRICAL SWITCH Filed Aug. 28, 1963 2Sheets-Sheet 2 Zasara Suzuh INVENTOR.

BY MMMWM m United States Patent 3,242,282 SNAP-ACTION PLUNGER-OPERATEDELECTRICAL SWITCH Masai-u Suzuki, Hekinan, Aichi-Prefecture, Japan,assignor to Kabushikikaisha Tokai Rika Denki Seisakusho,Nishikasugai-gun, Aichi-Prefecture, Japan Filed Aug. 28, 1963, Ser. No.305,065 Claims priority, application Japan, July 13, 1963, 38/ 38,149 1Claim. (Cl. 200-76) This invention relates to a snap-actionplunger-operated electrical switch wherein the contacts are opened andclosed with a high speed snap-action through a reversing means operatedby a plunger or push-button.

An object of the present invention is to provide a simplified and lessexpensive snap-action plunger-operated electrical switch construction.

A further object of the invention is to provide a snapactionplunger-operated electrical switch including a relatively shortoperating plunger and having minimum overall dimensions.

A further object of the invention is to provide a snapactionplunger-operated electrical switch particularly designed for use in abrake controlling circuit for motor vehicles.

According to the above mentioned objects, an embodiment of the presentinvention is explained in detail in the following with reference to thedrawings and the invention is defined in the appended claims.

In the drawings, FIGURE 1 is a vertically sectioned elevation of anembodiment of the push-button switch according to the present inventionas the circuit is closed;

FIGURE 2 is a vertically sectioned elevation of the same embodiment asopened;

FIGURE 3 is a partly sectioned side view of the embodiment illustratedin FIGURE 1;

FIGURE 4 is a bottom surface view of the same.

As illustrated in the accompanying drawings, 1 is a case body onenclosure in which fixed contact points 2 are arranged in a row andembedded. A movable contact piece or bridging member 3 is arranged tocontact with and separate from the fixed contact points and is securedthrough a washer 5 and an insulator 5' to the center of a channel-shapedspring means 4 for a resilient reversing mechanism :1 contained in thecase body 1. A tubular mounting member 6 is secured to the upper part ofthe case body 1. A push-button or plunger 7 is inserted through member6. A coil spring 9 is fitted and interposed between the engaging part 8of said pushbutton 7 and the case body 1, and its forward end has anengaging part 10 in the form of a concave ring at the forward end of thepush-button 7 and engaged with concave engaging parts 12 at the innerends q of reversing resilient pieces 11 engaged at the outer ends p asopposed to each other with the insides of resilient arms 4 of saidchannel-shaped spring means 4. When the push-button 7 is released, as inFIGURE 1, the resilient-pieces 11 will assume the form of an angle withthe push-button 7 in the center, the right and left resilient arm-s 4'will exert a bias in the inclined directions of the reversing resilientpieces 11 and thereby the channel-shaped spring means 4 will be presseddownward so that the movable contact piece 3 may be pressed in resilientcontact with the fixed contact points 2. The movable contact piece 3includes downwardly ofiset contacts which are centered in respect to thespring means 4. The spring means 4 are centered and its biasing pressureis limited by the lateral walls of the enclosure against which the arms4', 4' abut when in a downward contact making position. The engagingpart 10 at the forward end of the push-button 7 is so adjusted that,when the push-button 7 is pushed down,

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the engaging parts q of the reversing resilient pieces 11 may reach aposition below the engaging parts p of the resilient arms 4'.

Lead wires 13 are connected to the fixed contacts, and a fastening nut14 is screwed to the mounting member 6. Part 15 is an upper cover of thecase body 1.

The operation of the above described formation will now 'be explained.First of all, when the push-button 7 is pushed down from the positionshown in FIGURE 1, it will compress the spring 9 and will move down tothe position shown in FIGURE 2. In such case, as the engaging part 10 atthe forward end of the push-button 7 moves down, it will gradually pushdown the engaging parts q of the reversing resilient pieces 11 opposedto each other. Until said engaging parts q reach the same position asthe level of the engaging parts p of the resilient sides 4', that is, adead center, the resiliency of each of said reversing pieces 11 will actdiagonally downward. But, when the engaging parts q fall past theposition of dead center, the reversing resilient pieces 11 will quicklyreverse and jack up the engaging parts p of the resilient sides 4' whilepressing and expanding the resilient sides 4 outward and will form areverse angle with the forward end engaging part as a center. Since adiagonally upward bias will be given to each of the resilient arms 4'along the reversed form of the reversing resilient pieces 11, thechannel-shaped plate 4 will be pushed upward as a whole and the movablecontact piece 3 will be separated from the fixed contact points 2 sothat the circuit is opened.

Then, when push-button 7 is released, by the returning force of thespring 9, the push-button 7 will be pushed up, the direction of theaction of the tension of the reversing resilient pieces 11 will bechanged over to the state shown in FIGURE 1 from the state in FIGURE 2.Thereby the reversing resilient pieces 11 will be reversed and themovable contact piece 3 will be again pressed into contact with thefixed contact points 2 so that the circuit is closed.

According to the present invention, as described above, when thepush-button is pushed, the movable contact piece will be separated fromthe fixed contact points so that the circuit may be opened. When thepush-button is released, the movable cont-act piece will be brought intocontact with the fixed contact points so that the circuit may be closed.The contact and separation of the movable contact piece can be madepositively without any malfunction by the quick switching operation ofthe resilient reversing mechanism including the reversing resilientpieces. The contact deterioration caused by separation of the contactpoints in the switching operation can be perfectly prevented. In casethe movable contact piece is in contact with the fixed contact pointsand the circuit is closed, said contact piece will be positivelyoperating always with a constant contact pressure. Therefore, there isan effect that the movable contact piece can be prevented fromaccidentally breaking the contact state and opening the circuit. Themechanism is so simple and small and can be so cheaply manufactured thatit can be applied to various uses and is adapted specifically to a brakeswitch for automobiles.

Though the present invention has been explained in the above withreference to the specific embodiment, it is to be understood that thisembodiment can be modified in any manner within the scope of the presentinvention described in the appended claim.

What is claimed is:

A normally closed, snap-action plunger-operated switch comprising, incombination, a switch enclosure having lateral wall means; a pair ofcontacts in spaced relation on one end wall of said enclosure fixed; atubular mounting member extending from an opposite end wall of saidenclosure substantially perpendicular to said one end wall; a-relativelyelongated plunger slidably mounted through said member and extendinginto said enclosure; means limiting outward movement of said plunger; acontact bridging member engageable with said contacts including ofisetprojecting contacts centered in respect to said plunger; and togglejoint snap-action support means supporting said bridging member on theinner end of said plunger; said support means including a substantiallyU-shaped spring member, having a base secured to said bridging memberand a pair of resilient arms extending outwardly from the ends of saidbase, and a pair of reversing pieces each having an outer end fulcrummedin a respective arm at a short distance from the outer end of the latterand an inner end supportingly fulcrummed on said plunger; said reversingpieces normally extending upwardly and inwardly from the arms with saidbridging member engaged with said contacts under pressure with saidplunger at its limit of outward movement and the outer ends of said armsengaging said lateral wall means for limiting outward movement thereofin order to control the contact engaging pressure and for centering saidofifset projecting contacts of said bridging member with said fixedcontacts; said plunger, when pressed inwardly, moving the inner ends ofsaid reversing pieces downwardly to spread said arms apart until saidreversing pieces pass dead center, whereupon the pressure of said armson said reversing pieces snaps the latter to positions in which theyextend downwardly and inwardly from said arms and snap said springmember and said bridging member away from said contacts; the outer endsof said arms abutting said opposite wall of said enclosure after arelatively short movement of said bridging member; said spring memberand said reversing pieces being free of supporting engagement with saidenclosure.

References Cited by the Examiner UNITED STATES PATENTS 1,011,754 12/1911Cubitt 200-76 2,332,911 10/ 1943 Hausler 20076 2,384,412 9/1945 Woods20076 2,598,856 6/1952 Swan et a1. 20076 3,017,471 1/1962 Karch 20076ROBERT K. SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.

H. B. ODONNELL, Assistant Examiner.

